Surgeons can adjust various parameters of a surgical lamp to achieve good illumination of an operating site during surgical procedures. Such parameters may include a position and/or an orientation of a lamp body of the surgical lamp, a focus of light beams radiated from the surgical lamp, and an intensity of light radiated from the surgical lamp (e.g., an illuminance on the operating site). The position and/or the orientation of the lamp body is typically adjusted (thereby causing an adjustment of a light field generated by the lamp body) by the surgeon. The surgeon may effect such changes by manipulating a sterile handle attached to the lamp body to move (e.g., swivel) the lamp body to a desired position and/or desired orientation. In some cases, repositioning the handle may cause a change in an intersection point of the light beams radiated from the lamp body.
Some surgical lamps may include mechanisms for measuring a distance between the lamp body and the operating site and accordingly correct the intensity of the radiated light in order to maintain a constant central illuminance on the operating site. In such surgical lamps, while the central illuminance is adjusted, the light field diameter does not change because light sources of the surgical lamp are non-adjustable, and parallel spotlights that may otherwise address this problem are not implemented in such optical setups.